Tapering mechanism for sawmill knees



Nov. 24, 1931. R. LANGILL ET AL TAPERING MECHANISM FOR SAWMILL KNEES Filed May 7, 1927 2 Sheets-Sheet l BY @M #1MM/@MMM INVENTOR.

Y ATTORNEY.

Nov. 24, 1931. R. LANGILL ET Al.

TAPERING MECHANISM FOR SAWMILL KNEES Filed May '7, 1927 2 Ishams-sneer 2' I N VEN TOR.

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ATTORNEYS Patented Nov. 24, 1931 UNITED? sra'rss TENT OFFICE ROSS LANGILL AND STANLEY B. LANGILL, OF MENOMENEE, MICHIGAN, ASSIGNORS TO THE PRESCOTT COMPANY, OF MENOMINEE, MICHIGAN, A CORPORATION 0F MICHI- GAN TAPERING MECHANISM FOR SAWMILL KNEES Application led May 7, 1927. Serial No. 189,522.

rlhis invention relates to a tapering mechanism for the knees of saw mill carriages.

An object of the invention is to provide a tapering mechanism of this character wherein the tapering movement is imparted to the knees by power means, `and yet the knees are automatically held in any position to which they are adjufted.

Another object is to provide a tapering mechanism which is simple and durable in construction, reliable, effective and readily controllablein operation and easy and comparatively inexpensive to manufacture.

A further object is to provide a tapering mechanism embodying cushioning means for absorbing the shocks and strains to which the knees are subi ected. and especially for absorbing the shockQ incident to the impact of the log with the knees.

In carrying out the present invention the knees on the saw mill are mounted on the head blocks for movement transversely of the carriage in the usual manner, and the slides, which may be racks, are fitted in the base of the knee for sliding movement in the conventional wav. These slides are actuated from a set shaft. and the tapering is effected by adiusting the knees relative to the slides or racks.

In its broader aspects the present invention proposes the provision of fluid pressure actuated power means between the knee and the slide for movinf; the knee relative to the slide and in conjunction with this Huid pressure actuated power means utilizes holding means which tends to and unless released, docs maintain the knee in fixed position relative to the slide. The holding means may comprise a cvlinfler fixed. to the knee and a piston operating in the cylinder and connected with the slide. In the cvlinder of the holding means a confined fluidV is contained and the cylinder and the piston of theholding means when moved relative to each other encounter the resistance of the confined fluid. A bypass, preferably somewhat restricted, is provided around the piston of the holding' means, and in this bvpass a shut-off valve is placed. The shut-off valve is biased to close position and is closed at all times except when Huid pressure is applied to the power means, whereupon the shut-oli' valve is automatically opened by the fluid pressure as it is subjected to the action of the iuid pressure. The connection between the pitons of the power means and the slide or rack embodies suitable cushioning means such as a spring which serves to take up shocks and relieves the taiering mechanism and other elements of the saw mill of the stress incident to such shocks.

Other objects and advantages reside in certain novel features of the construction, ar-

rangement and combination of parts'which i will be hereinafter `more fully described and particularly pointed out in the appended claims, reference being had to the accompanying drawings forming a part of this specification, and in which:

Figure 1 is a plan view showing a knee of a saw milll equipped with a tapering mechanism embodying the present invention.

Figure 2 is a view partly in side elevation and partly in section further showing the knee and tapering mechanism of Figure 1.

Figures 3, 4 and 5 are views in transverse section taken on lines 3 3, 4-4 and 5 5 respectively of Figure 2.

Figure 6 is a view partly in side elevation and partly in section taken on line 6-6 of Figure l, and

Figure 7 is a fragmentary View in horizontal section taken on line 7*-7 of Figure 2 and illustrating the construction of the metering valve and pressure controlled shut-olf valve of the bypass associated with the holding cylinder.

Referring to the drawings, the numeral 1 (see Figures 3 and 4) designates a portion of the head block of a saw mill carriage. A knee is designated generally.7 at 2 and has guides 3 in its base, the guides 3 being slid-- ably interiitted with the portionsl of the head block. A slide 4 is also slidablv interitted as at 5 with the base of theknee to permit the knee to partake of tapering movement, that is, sliding movement hack and forth along and relative to the slide 1. This slidei1 is shown as having on its under face a rack 6 ldesigned for coaction with the pinion (not shown) on the usual set shaft. It

is to be understood, however, that the slide 4 may be actuated from the set shaft in any conventional manner.

As illustrated to arvantage in Figures .il and 4, the knee 2 has side plates 7 and on these side plates T a cylinder assemblyy indicated generally at 8 is mounted by means of depending' attachingbraclzets 9 integrallj.' formed with or otherwise rigidly secured to the cylinder assembly and bolted as at lll to the side plate .7 ot the knee.

The cylinder assembly 8 .includes two power cylinders 1L one at each side oil. the assembly, and an intermediate holding' cylinder 12 located between the power cylinders ll. End plates or heads 1?) and i4 are provided for the cyliniil r assembly and are tastened in position by any suitable means, as tor instance by stud bolts. Suitable pecl'- ing. such as the usual grailrets, may he interposed between the ends or" the cylinder assembly 8 and the heads i3 and l-l. ln cach power cylinder ll a power piston i6 is operatively fitted, each power piston harina' a piston rod i7 slidable through a stalling bev 18 provided on the head 1?.

The piston rods 17 are fined, as tor examplev4 by means of pins i9 to a crosss head designated generally at 20. and the cross head is connected in a manner which will be hereinafter more fully described with the upper end ot a standard 2l. The hase ot the stand ard Q1 is received between apertured ears provided on the slide 4 and within a groove 25 formed in the slide 4, the standard being Secured tothe ears by a pin lil which passes through the ears and through the stannard. The hase et the standard 2l is somewhat elongated, and one end ot the elongated hase hears against the ha ot the groove 25, while the other end of the elongated hase has set screws 26 threaded therethrough and held in adjusted. position by nuts Q17. The lower ends ot' the set screws are rounded and bear against the bottom ot the groove 25 to Secure the standard 2l in proper position on the slide 4.

Means provided tor supplying ifluid under pressure.y such as compre power cylinders il, and consists ot a fluid pressure supply line. 30 leading' trom any suitable source ot fluid under pressure to a control valve 3l which ma y be ot any suitable conventional type. The control valve 3l has a vent 32 leading); to the atmosphere and also connects with pipes 3257 and 34 leading to the cylinder heads lll and respectively (see Figure ,fis shown in Figure 4, the pipey 33 communica te. with a short vertical passagey 35 provided in the trout cylinder Vhead 13, and this passage communicates directly with a port 36 leading; into the front end oit the cylinder ll. on one side ot the assembly. The passage 35 also comun".- nicates with a transverse. branch passage El?,

#l air, to the which in turn communicates with a port 2:58 leading into the forward end of the other power cylinder 1l. Similarly, the pipe 34 communicates with a short i'assaye 39 in the rearward cylinder head 14 and the passage: 39 directly connects with a port Al() leadingl into the rearward end ot one power cylinder' ll. rlfhe passage 39 also communicates with a transif'erse branch passage jl-l which in turn connects with a port 42 leadin into the rearward end ot the other power cylinder ll. To make the heads 13 and leinterchangeable they are formed with plugged passa res 35 and 39 communicating with ports :h and 42 respectively. With this arranaenuan the valve Ell may be adjusted to simultaneously admit fluid pressure to the iorward ends ot both power cylinders, and to permit the fluid pressure to exhaust `from the rearward ends ot both power cylinders, therelr.' causing' the cylinders and the lince to more forwardly, the knee being advanced toward the saw line. 'll'hcn again` the falve Bl may be adjusted to admit tluid pressure to the rear *ard end ot both power cylindi-:rs 'll and permit the tluid pressure to exhaust trot the :forward ends oit both power nder:`l ll, whereby cylinders ll are moved ron-we rclj and the linee retracted.

For the purpose o't' holding' the linee in amv l 'i adjustment a piston 4.3 is operatively fitted in the cylinder l2 (see Figure. (l) and has a piston rod 4G secured tliereto andA projectingY through stutling' boxes 47 provided on the heads 13 and 14 ot the cylinder assembly.

rlhe cylinder l2 is filled with oil or other incompressible tluid which, being' confined. holds the piston 45 and cylinder l2 against relative movement and consequently prevent-s movement of the cylinder l2 and the linee 2 relative to the slide 4.

The, toi-ward end ot the piston rod lo is en, tended through openings 4S and 4l) proviiglrwl therefor in the front and rear cross members` 54 and respectively ot' the cross head Qd and also through an opening 5() provided in the upper end ot the standard 2l. the piston rod slidably fitting in the openings 48 and 50 but passing freely through the much larger opening' 49. is shown` the upper end of the standard 2l is located in the space between the front and rear cross membersI 5land and the. side members and 55a ol the crosshead 20. The forward eri'tremity ol' the piston rod 4(3.projects beyond the Al'ronl cross member 54 ot the crosshead and has nuts 5l and 52 threaded thereon.I the nut engaging the cross head and the nut 5l engaging the nut 52. A coil spring` 58 encircles the portion of the pistou rod 4G located between (and also engages) the 'forward cross member 54 of the crosshcad Q() and the upper end ot the standard 2l.

The rearward. 'tace o't the upper end ot the standard Q1 is engageahle with a stop nut 5o lili suitably fixed to the piston rod 46, this nut 56 limiting the forward movement of the crosshead 2() relative to the standard 21. Figure 1 shows the crosshead 20, standard 21 and nut 56 in the normal or rest Vposition of these parts. Upon impact of a log on the face of the knee 2, the knee and cylinder assembly are forced rearwardly and exert a rearward thrust or pull on the piston rods 46 and 17. The shock of this force or thrust is taken up by the spring 53, which yields slightly at this time. As the spring 53 yields the crosshead 20 moves rearwardly relativeV to the standard 21, the piston rod 46 sliding through the standard 21. However, immediately after impact, the spring again eX- pands and moves the crosshead 20, piston rods 17 and 46, the cylinder assembly 8 and the knee 2 forwardly until the stop nut 56 engages the standard 21. The opening 49 is larger than the nut 56 to allow nut 56 to pass thro-ugh the opening in the assembly. It is to be understood that in lining up the knees the nuts 51 and 52 may either be backed off to some extent or may be tightened up as may be necessary to effect the required ad'ustment. This arrangement of the crosshead 20, standard 21, nuts 51 and 52, spring 53 and stop nut 56 also provides a cushioning con-V nection between the knee 2 and the rack or slide 4.

In order to permit movement of the knee 2 at the proper time a bypass 60 is provided and extends from one end o f the cylinder 12 to the other, the bypass communicating with the cylinder through passages 61 in the cylinder heads 13 and 14. In this bypass 60, a metering valve 62 of any suitable construction is incorporated to restrict the passage of fluid through the bypass to a desirable degree.

A pressure controlled shut-off valve 63 is also incorporated in the bypass 60 and comprises a valve casing 64 having a ported parti tion 65 therein. The sections 6()a and 60h of the bypass 60 communicate with the interior of the valve casing 64 on the opposite sides of the partition 65. A piston valve 66 is fitted in the casing 64 for sliding movement, and it has a portion 67 of such size and so machined or otherwise formed as to snugl engage the inner periphery of the lower portion of the valve casing and also the inner periphery of the ported partition 65 to block the passage in the valve casing and shut off any flow of fluid in the bypass in the closed position of the valve. Above this portion 67, the valve 66 has a peripheral recess 68 which, when the valve is lowered to align the recess 68 with the partition 65 permits the oil or other fluid to flow past the ported partition 65 and through the valve casing .and consequently also through the bypass. The upper end of the piston valve 66 is closed by a head 69. An expansible coil spring is positioned in the valve .casing 63 with one end engaging the lower end of the valvecasing and its other end engaging the head 69 of the piston valve 66, whereby the spring 70 serves to move the valve to the closed-position shown in Figure 7, wherein the portion 67 orn the valve blocks the flow ot oil through the bypass.

To cause the valve 66 to be automatically opened when suicient fluid pressure is sup plied to either end of the power cylinders to cause tapering, the heads 13 and 14 of the power cylinders have ports 71 and 72 therein (see Figures 4 and 5), the ports 71 and 72 communicating with passages 73 and 74.

Vwhich in turn communicate with the ends of a pipe A T 7 6 is incorporated in the pipe 75 and communicates with a pipe 7'( which leads into the valve casing 63 ad]acent the head 69 of the valve 66. Thus, whenever iiuid pressure is supplied to the cylinders 11, it flows into one end or the other' of the pipe 75, and from the pipe 75 into the pipe 77 and acts on the head 69 of the piston valve 66 to move the valve 66 against the action of the spring 70 whereby to open the valve 66 and the bypass 60. This permits the oil to pass 'from one end of the cylinder 12 to the other, and consequently permits the cylinder 12 to move relative to its piston 45. Until the cylinder 12 is free to move, the power cylinders are locked in position thereby, but with the arrangement described, whenever the valve 31 is manipulated to admit fluid under pressure to the power cylinders, the bypass is automatically opened to release the holding means. However, even when the bypass is opened, the metering valve 62 continues to exercise its function to check the movement of the cylinders and knee, thereby insuring an even and steady motion and preventingl the setting up of undesirable momentum in the movingparts or a high rate of flow in. the oil. As soon as the valve 31 is turned to aposition to shut ott the supply of fluid pressure the spring 70 automatically closes the valve 66, thereby blocking the bypass and locking the parts in adjusted position.

The invention claimed is:

1. A tapering device for a sawmill knee having a slide through which the knee is set and comprising power and check cylinders fixed to the knee, pistons fitted in the cylinders and having piston rodsprojecting exteriorly thereof, a cross head fixed to one or. more power cylinder piston rods, a check cylinder piston rod being slidable through said cross head, means for limiting the movement in one direction of said last mentioned piston rod relative to the cross head, a standard fixed to the slide and having an opening in which said last mentioned pistou rod is slidably fitted, a spring between the standard and the cross head, and means for limiting the movement in one direction of the last mentioned piston rod relative to the standard.

2. A tapering device for sawmill knees havingl a slide through which the knee is set and comprising power and check cylinders fixed to the knee, pistons fitted in the cylinders and having piston rods projecting eXteriorly thereof, a cross head fixed to one or more power cylinder piston rods, said cross head including' front and rear cross members and a lengthwise opening between said cross members, said cross members also having openings through which a check cylinder piston rod extends, adjustable means on the forward end of said last mentioned piston rod engageable With the front cross member for limiting` the movement in one direction of said last mentioned piston rod relative to the cross head, a standard lixed to the slide and projecting up into the lengthwise opening of the cross head, said standard having an opening at its upper end in which the last inentioned piston rod is slidably fitted, a spring on the last mentioned piston rod having one end abutting the front cross member of the cross head and having` its other end abutting the standard, and a stop collar secured to the last mentioned piston rod and engageable with the standard, the rear cross member having its opening sufficiently large to permit of passage of said stop collar therethrough.

1n Witness whereof, We hereto atiix our signatures.

ROSS LANGILL. STANLEY B. LANGILL. 

